mirror of https://gitee.com/openkylin/linux.git
dm verity: clean up duplicate hashing code
Handle dm-verity salting in one place to simplify the code. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Sami Tolvanen
Mike Snitzer
parent
ba503835ad
commit
6dbeda3469
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@ -172,6 +172,84 @@ static sector_t verity_position_at_level(struct dm_verity *v, sector_t block,
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return block >> (level * v->hash_per_block_bits);
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}
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/*
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* Wrapper for crypto_shash_init, which handles verity salting.
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*/
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static int verity_hash_init(struct dm_verity *v, struct shash_desc *desc)
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{
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int r;
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desc->tfm = v->tfm;
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desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
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r = crypto_shash_init(desc);
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if (unlikely(r < 0)) {
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DMERR("crypto_shash_init failed: %d", r);
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return r;
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}
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if (likely(v->version >= 1)) {
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r = crypto_shash_update(desc, v->salt, v->salt_size);
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if (unlikely(r < 0)) {
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DMERR("crypto_shash_update failed: %d", r);
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return r;
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}
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}
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return 0;
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}
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static int verity_hash_update(struct dm_verity *v, struct shash_desc *desc,
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const u8 *data, size_t len)
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{
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int r = crypto_shash_update(desc, data, len);
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if (unlikely(r < 0))
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DMERR("crypto_shash_update failed: %d", r);
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return r;
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}
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static int verity_hash_final(struct dm_verity *v, struct shash_desc *desc,
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u8 *digest)
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{
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int r;
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if (unlikely(!v->version)) {
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r = crypto_shash_update(desc, v->salt, v->salt_size);
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if (r < 0) {
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DMERR("crypto_shash_update failed: %d", r);
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return r;
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}
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}
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r = crypto_shash_final(desc, digest);
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if (unlikely(r < 0))
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DMERR("crypto_shash_final failed: %d", r);
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return r;
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}
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static int verity_hash(struct dm_verity *v, struct shash_desc *desc,
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const u8 *data, size_t len, u8 *digest)
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{
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int r;
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r = verity_hash_init(v, desc);
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if (unlikely(r < 0))
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return r;
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r = verity_hash_update(v, desc, data, len);
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if (unlikely(r < 0))
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return r;
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return verity_hash_final(v, desc, digest);
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}
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static void verity_hash_at_level(struct dm_verity *v, sector_t block, int level,
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sector_t *hash_block, unsigned *offset)
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{
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@ -252,10 +330,10 @@ static int verity_handle_err(struct dm_verity *v, enum verity_block_type type,
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* If "skip_unverified" is false, unverified buffer is hashed and verified
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* against current value of io_want_digest(v, io).
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*/
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static int verity_verify_level(struct dm_verity_io *io, sector_t block,
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int level, bool skip_unverified)
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static int verity_verify_level(struct dm_verity *v, struct dm_verity_io *io,
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sector_t block, int level, bool skip_unverified,
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u8 *want_digest)
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{
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struct dm_verity *v = io->v;
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struct dm_buffer *buf;
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struct buffer_aux *aux;
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u8 *data;
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@ -272,74 +350,71 @@ static int verity_verify_level(struct dm_verity_io *io, sector_t block,
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aux = dm_bufio_get_aux_data(buf);
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if (!aux->hash_verified) {
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struct shash_desc *desc;
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u8 *result;
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if (skip_unverified) {
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r = 1;
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goto release_ret_r;
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}
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desc = io_hash_desc(v, io);
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desc->tfm = v->tfm;
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desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
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r = crypto_shash_init(desc);
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if (r < 0) {
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DMERR("crypto_shash_init failed: %d", r);
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r = verity_hash(v, io_hash_desc(v, io),
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data, 1 << v->hash_dev_block_bits,
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io_real_digest(v, io));
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if (unlikely(r < 0))
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goto release_ret_r;
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}
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if (likely(v->version >= 1)) {
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r = crypto_shash_update(desc, v->salt, v->salt_size);
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if (r < 0) {
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DMERR("crypto_shash_update failed: %d", r);
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goto release_ret_r;
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}
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}
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r = crypto_shash_update(desc, data, 1 << v->hash_dev_block_bits);
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if (r < 0) {
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DMERR("crypto_shash_update failed: %d", r);
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goto release_ret_r;
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}
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if (!v->version) {
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r = crypto_shash_update(desc, v->salt, v->salt_size);
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if (r < 0) {
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DMERR("crypto_shash_update failed: %d", r);
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goto release_ret_r;
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}
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}
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result = io_real_digest(v, io);
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r = crypto_shash_final(desc, result);
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if (r < 0) {
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DMERR("crypto_shash_final failed: %d", r);
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goto release_ret_r;
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}
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if (unlikely(memcmp(result, io_want_digest(v, io), v->digest_size))) {
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if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_METADATA,
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hash_block)) {
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r = -EIO;
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goto release_ret_r;
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}
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} else
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if (likely(memcmp(io_real_digest(v, io), want_digest,
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v->digest_size) == 0))
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aux->hash_verified = 1;
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else if (verity_handle_err(v,
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DM_VERITY_BLOCK_TYPE_METADATA,
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hash_block)) {
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r = -EIO;
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goto release_ret_r;
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}
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}
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data += offset;
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memcpy(io_want_digest(v, io), data, v->digest_size);
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dm_bufio_release(buf);
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return 0;
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memcpy(want_digest, data, v->digest_size);
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r = 0;
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release_ret_r:
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dm_bufio_release(buf);
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return r;
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}
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/*
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* Find a hash for a given block, write it to digest and verify the integrity
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* of the hash tree if necessary.
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*/
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static int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io,
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sector_t block, u8 *digest)
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{
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int i;
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int r;
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if (likely(v->levels)) {
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/*
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* First, we try to get the requested hash for
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* the current block. If the hash block itself is
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* verified, zero is returned. If it isn't, this
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* function returns 1 and we fall back to whole
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* chain verification.
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*/
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r = verity_verify_level(v, io, block, 0, true, digest);
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if (likely(r <= 0))
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return r;
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}
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memcpy(digest, v->root_digest, v->digest_size);
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for (i = v->levels - 1; i >= 0; i--) {
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r = verity_verify_level(v, io, block, i, false, digest);
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if (unlikely(r))
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return r;
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}
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return 0;
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}
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/*
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* Verify one "dm_verity_io" structure.
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*/
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@ -349,54 +424,21 @@ static int verity_verify_io(struct dm_verity_io *io)
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struct bio *bio = dm_bio_from_per_bio_data(io,
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v->ti->per_bio_data_size);
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unsigned b;
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int i;
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for (b = 0; b < io->n_blocks; b++) {
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struct shash_desc *desc;
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u8 *result;
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int r;
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unsigned todo;
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struct shash_desc *desc = io_hash_desc(v, io);
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if (likely(v->levels)) {
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/*
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* First, we try to get the requested hash for
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* the current block. If the hash block itself is
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* verified, zero is returned. If it isn't, this
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* function returns 0 and we fall back to whole
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* chain verification.
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*/
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int r = verity_verify_level(io, io->block + b, 0, true);
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if (likely(!r))
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goto test_block_hash;
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if (r < 0)
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return r;
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}
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memcpy(io_want_digest(v, io), v->root_digest, v->digest_size);
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for (i = v->levels - 1; i >= 0; i--) {
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int r = verity_verify_level(io, io->block + b, i, false);
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if (unlikely(r))
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return r;
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}
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test_block_hash:
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desc = io_hash_desc(v, io);
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desc->tfm = v->tfm;
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desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
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r = crypto_shash_init(desc);
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if (r < 0) {
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DMERR("crypto_shash_init failed: %d", r);
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r = verity_hash_for_block(v, io, io->block + b,
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io_want_digest(v, io));
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if (unlikely(r < 0))
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return r;
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r = verity_hash_init(v, desc);
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if (unlikely(r < 0))
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return r;
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}
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if (likely(v->version >= 1)) {
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r = crypto_shash_update(desc, v->salt, v->salt_size);
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if (r < 0) {
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DMERR("crypto_shash_update failed: %d", r);
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return r;
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}
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}
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todo = 1 << v->data_dev_block_bits;
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do {
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u8 *page;
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@ -407,37 +449,27 @@ static int verity_verify_io(struct dm_verity_io *io)
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len = bv.bv_len;
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if (likely(len >= todo))
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len = todo;
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r = crypto_shash_update(desc, page + bv.bv_offset, len);
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r = verity_hash_update(v, desc, page + bv.bv_offset,
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len);
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kunmap_atomic(page);
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if (r < 0) {
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DMERR("crypto_shash_update failed: %d", r);
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if (unlikely(r < 0))
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return r;
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}
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bio_advance_iter(bio, &io->iter, len);
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todo -= len;
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} while (todo);
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if (!v->version) {
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r = crypto_shash_update(desc, v->salt, v->salt_size);
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if (r < 0) {
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DMERR("crypto_shash_update failed: %d", r);
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return r;
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}
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}
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result = io_real_digest(v, io);
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r = crypto_shash_final(desc, result);
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if (r < 0) {
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DMERR("crypto_shash_final failed: %d", r);
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r = verity_hash_final(v, desc, io_real_digest(v, io));
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if (unlikely(r < 0))
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return r;
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}
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if (unlikely(memcmp(result, io_want_digest(v, io), v->digest_size))) {
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if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_DATA,
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io->block + b))
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return -EIO;
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}
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if (likely(memcmp(io_real_digest(v, io),
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io_want_digest(v, io), v->digest_size) == 0))
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continue;
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else if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_DATA,
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io->block + b))
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return -EIO;
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}
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return 0;
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